The keyboard shortcut is trying to use xscreensaver which is not installed and should be using lxlock.
~/.config/openbox/lubuntu-rc.xml
Currently:
<!-- Lock the screen on Ctrl + Alt + l--> <keybind key="C-A-l"> <action name="Execute"> <command>xscreensaver-command -lock</command> </action> </keybind>
Change to:
<!-- Lock the screen on Ctrl + Alt + l--> <keybind key="C-A-l"> <action name="Execute"> <command>lxlock</command> </action> </keybind>
The keyboard shortcut is trying to use xscreensaver which is not installed and should be using lxlock.
~/.config/ openbox/ lubuntu- rc.xml
Currently:
<!-- Lock the screen on Ctrl + Alt + l-->
<command> xscreensaver- command -lock</command>
<keybind key="C-A-l">
<action name="Execute">
</action>
</keybind>
Change to:
<!-- Lock the screen on Ctrl + Alt + l-->
<command> lxlock< /command>
<keybind key="C-A-l">
<action name="Execute">
</action>
</keybind>